National Geographic: Superfish

She slices through the water's surface with explosive power. Sail, spear, and a half ton of muscle flash in the sun. Then just as suddenly she vanishes to resume her endless race through the open ocean. Her journeys are epic. Her life cycle, bizarre. She is a billfish, largest, fastest and most highly prized of all gamefish. Rarely caught on film, her astonishing story has never been fully told. Renowned for its formidable spear and sword-like bills, the species includes the spectacular marlin, swordfish, spearfish and sailfish. Embark on an extraordinary quest through some of the planet's most beautiful aquatic environments from the undersea canyons off Costa Rica to the bright tropical waters of the Great Barrier Reef in search of an elusive thousand pound, 15 foot marlin known as a grander.